Dimension measuring instrument

Abstract

This invention concerns a dimension measuring instrument comprising an encoder for converting a displacement of a spindle into an electric signal and an analogue indication device for electrically indicating a measured value, which has been obtained through processing of an output from the encoder, by a pattern including a scale or scales, a pointer and the like. The analogue indication device is provided with a scale indicating circuit for continuously indicating two or more scales different in scale interval from each other and a pointer indicating circuit for driving the pointer in accordance with the measured value and depending on the scale interval for the indication, and a range of dimension indication is expanded without deteriorating the reading accuracy within a predetermined range of dimension indication.

What is claimed is: 
     
       1. A dimension measuring instrument comprising: an encoder for converting a displacement of a spindle into an electric signal;   an analogue indication device for electrically indicating a measured value obtained through processing of an output from said encoder, said analogue indication device electrically indicating the measured value by a pattern including at least one scale and a pointer;   a scale indicating circuit included in said analogue indication device, said scale indicating circuit indicating at least one scale having different scale intervals in one scale row; and   a pointer indicating circuit included in said analogue indication device, said pointer indicating circuit driving said pointer in accordance with said measured value and depending on the scale intervals for the indication;   whereby a range of dimension indication is expanded without deteriorating the reading accuracy within a predetermined range of dimension indication.   
     
     
       2. A dimension measuring instrument as set forth in claim 1, wherein said scale indicating circuit is connected to a scale setter, and scales different in scale interval from each other are connected to each other, bordering on an indication scale mark corresponding to a limit value set by said scale setter. 
     
     
       3. A dimension measuring instrument as set forth in claim 2, wherein said scale setter is adapted to set tolerance values and the minimum scale interval. 
     
     
       4. A dimension measuring instrument as set forth in claim 1, wherein said scale intervals are successively enlarged from a boundary of a predetermined indication scale mark. 
     
     
       5. A dimension measuring instrument as set forth in claim 1, wherein said scale intervals are enlarged by several stages from a boundary of a predetermined indication scale mark. 
     
     
       6. A dimension measuring instrument as set forth in claim 1, wherein the scale indication patterns of several types are previously set, so that said scale indication patterns can be switched to one another by a scale change-over switch. 
     
     
       7. A dimension measuring instrument as set forth in claim 1, wherein said scale intervals are made small at a portion close to a target value and enlarged at portions in front and at the back of said target value. 
     
     
       8. A dimension measuring instrument as set forth in claim 1, wherein said scale indicating circuit can change the setting of the scale intervals and the scale spacings. 
     
     
       9. A dimension measuring instrument comprising: an encoder for converting a displacement of a spindle into an electric signal;   an analogue indication device for electrically indicating a measured value obtained through processing of an output from said encoder, said analogue indication device electrically indicating the measured value by a pattern including at least one scale and a pointer;   a digital indication device for digitally indicating said measured value;   a scale indicating circuit included in said analogue indication device, said scale indicating circuit indicating at least one scale having different scale intervals in one scale row; and   a pointer indicating circuit included in said analogue indication device, said pointer indicating circuit driving said pointer in accordance with said measured value and depending on the scale intervals for the indication;   whereby a range of dimension indication of said analogue indication device is expanded without deteriorating the reading accuracy within a predetermined range of dimension indication.